1. Technical Field
The present invention relates to a manufacturing method for a cooling unit, a cooling unit, an optical device, and a projector.
2. Related Art
As a cooling unit using a cooling fluid, there is a cooling unit that includes a cooling plate having a structure in which a metal pipe serving as a coolant path is arranged between inner surfaces of a pair of metal plates combined to be opposed to each other. This cooling plate is manufactured by forming a pipe housing groove larger than the metal pipe in at least one of the pair of metal plates and integrally combining the metal pipe and the pair of metal plates. In a manufacturing process of the cooling plate, a pressurized fluid is supplied into the metal pipe after the combination to expand a diameter of the metal pipe and closely attach the metal pipe in the pipe housing groove (see, for example, JP-A-2002-156195).
In a manufacturing method for the cooling unit, the metal plates and the metal pipe are combined by forming the pipe housing groove in a reverse taper shape with respect to a mating surface of the metal plate and, in expanding the diameter of the metal pipe, causing an edge portion (an undercut portion) of the groove to cut into the metal pipe.
However, in the manufacturing method, cutting using a special cutting tool is required for forming the undercut portion. Therefore, it is difficult to realize a reduction in cost and cope with a reduction in size of the cooling unit.